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First roasts with data logger

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  • #16
    Re: First roasts with data logger

    Originally posted by 5D54585A570D3B0 link=1318770716/12#12 date=1319467076
    Oh so many questions.
    ...and NO correct answers except the roast that tastes the best was roasted better than your previous roasts.

    Serious!

    Originally posted by 7F5E48525C5552555C794278545D5D5E5E3B0 link=1318770716/13#13 date=1319486286
    drinkable range - I can experiment with time/ramps etc.
    Exactly. Small single changes to a "known good" heat application will yeild different results. They might be better results for your taste but wont be any more "correct".

    The beauty of home roasting is that you can roast to suit your own taste.

    The inverse of that is that the burden of commercial roasting is that you have to roast to an "average" taste.

    Originally posted by 5A494F565A553B0 link=1318770716/14#14 date=1319504347
    Generally speaking, is the final roast colour dependent on the end temp
    Yep. A handfull of seconds at the end of the roast will certainly change the colour as will taking too long to cool it.

    ...but dont get too hung-up on colour. Using the Roast Monitor you can easily see the temperature and go by that, a couple of degrees later at the end of the roast will certainly change the result in the cup.

    Originally posted by 5A494F565A553B0 link=1318770716/14#14 date=1319504347
    Are the cracks releated to a particular temp (for a particular bean)?
    Most arabica* beans will crack at the same points (ish) for the same heat application. It might be 190-200C for first crack and 215-225C for second.

    Typically the cracks will happen within a degree or two every time, the 10C span above is because everyone will have a different reading where the cracks happen in their own setup but once you know where your setup cracks... it should then they will do so there most of the time.

    *range of cracks for arabica... Robusta crack a few degrees later as a rule of thumb.

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    • #17
      Re: First roasts with data logger

      Thanks for the great info Andy! [smiley=thumbsup.gif]

      Might need to work on consistency and control now, esp at the end of the roast when it all goes quickly, in reagrd to taking the heat off, dumping, cooling.

      Might try sucking the beans straight out of the corretto into the sieve of the bean cooler.

      Cheers

      Comment


      • #18
        Re: First roasts with data logger

        Originally posted by 3724223B3738560 link=1318770716/16#16 date=1319508321
        Thanks for the great info Andy!
        Always happy to share.

        Originally posted by 3724223B3738560 link=1318770716/16#16 date=1319508321
        Might need to work on consistency and control now, esp at the end of the roast when it all goes quickly, in reagrd to taking the heat off, dumping, cooling.
        You can see beans change colour in the cooling tray of a commercial roaster in the first few seconds after dropping!

        Cooling is important but even slow cooled is ok if you allow for it as part of your roast technique... just finish the heat a little earlier to allow for the thermal mass overrun as you start cooling.

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        • #19
          Re: First roasts with data logger

          Thats very interesting.

          I guess its more critical to be consistent so the results are repeatable, more so than using a particular technique.

          Cheers

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          • #20
            Re: First roasts with data logger

            Originally posted by 3625233A3639570 link=1318770716/14#14 date=1319504347
            Regarding this, on my roasts, I find that if I dont dump as soon as I start hearing second crack, the beans end up roasted very dark.  Maybe my temp is not tapering off sufficiently towards the end?  Generally speaking, is the final roast colour dependent on the end temp or what is happening temp wise during the roast?
            While I really dont have much to add to all of Andys great info, just a quick response to this specific point…
            I think the registered temp of 2C can vary depending on the probe placement - in my Corretto setup (with probe is back left corner, 5mm off the bottom of the pan under the bean mass) both 1st & 2nd crack normally hit at the lower end of Andys ballpark figures - eg I can almost set my watch to first crack beginning at 199 degrees, and the first pops of 2C at 219 degrees. So for me, even taking the temp up to 222, I still end up with a colour in the CS8-ish range.
            But if your setup reads higher (maybe different pan, probe placement, airflow, bean mass) then this will certainly change the registered profile (but not the actual bean temperatures - just how your probe measures them :-/.)
            That said, based on my experiences, I found that my first great baseline roast success (after 30+ roasts of mixed success) finally happened when I roasted 3-4 degrees higher than where 2C began (reading 219 on my DMM) - before that all my roasts lacked body & aroma, had a bit of a generic flavour and a hint of sourness as an espresso.
            Those few degrees at the end blew my mind!

            So enjoy the journey - experiment, taste and tinker
            Matt

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            • #21
              Re: First roasts with data logger

              I just bought the DMM and membership card from beanbay last week.
              According to the courier website, it has arrived my uni last Friday, but I have not heard anything from uni internal mail system yet (what a slacker).
              Thanks for artman to start this thread, its exactly I am looking for.
              I try to be prepared when I start my first Corretto with DMM.
              I have download the roaster monitor and RML in my computer for a while, can not wait to use them!!

              Colin

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              • #22
                Re: First roasts with data logger

                Awesome info, thanks for that. Will give this a bash next time I roast and report back.

                I will move my probe too (later on - dont want to change more than one thing at a time), currently its closer to the gun entry point, will move it to the opposite corner and lower down (its in the top half of the bean mass atm), this should hopefully be less influenced by the air temp of the gun. Although like you guys mention, its all relative anyway.

                Cheers

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                • #23
                  Re: First roasts with data logger

                  Forgot to ask, what sort of green bean weight do you normally roast Matt?

                  I know how you feel Colin!! I couldnt wait for it to arrive, then when I got it had trouble getting the software running on my laptop, all seems to be working now though!

                  Also might try using the software to monitor intake temps in my car, to see how effective the new water to air intercooler is.

                  Cheers

                  Comment


                  • #24
                    Re: First roasts with data logger

                    Originally posted by 5645435A5659370 link=1318770716/22#22 date=1319533315
                    Forgot to ask, what sort of green bean weight do you normally roast Matt?
                    I now roast 350g per batch, which when it looses some weight, fills a 250g valved bag perfectly (enough for about a week for us). I found that any less than this made getting a stable, consistent temperature rise hard, but going too much over this (went to 500g at one stage) made controlling the temp in the bigger bean mass hard to manage - eg when you tried to back off at 2C it could keep rising for a fair while. As it is, with 350g, I tend to raise the gun at 195 degrees, so that it hits 2C more gently. I can then get a pretty good gentle ramp from 1C to 2C.

                    Originally posted by 5645435A5659370 link=1318770716/21#21 date=1319533046
                    I will move my probe too (later on - dont want to change more than one thing at a time), currently its closer to the gun entry point,
                    This might be where a temp discrepancy comes from - the gun could be heating the probe more than the bean mass. While it is relative to some degree setup to setup, it can be hard to analyse the results others have posted. I spent a while dropping beans at 216-218 degrees, because these figures kept cropping up. Then Mal gave me a ballbark of 223-225 on a corretto for espresso - and Bobs your mothers uncle!

                    The probe in my setup (which I positioned based after a lot of research on this site!) comes in from the LH side right through the BM casing, sticks out about 25mm into the pan, 5mm off the base and about 25mm in from the back - which means with 350g it is well and truly covered by beans. And, based on Andys figures, seems pretty much on the money with whats going on in bean land ;D

                    Now, I want to know how youre planning to modify the water to air intercooler to cool your beans!





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                    • #25
                      Re: First roasts with data logger

                      Ahh.. so much knowledge to be shared. Thanks guys.

                      I will definitely try extending my temp that extra few degrees at the end of second crack in my next roast.

                      So far, so good. I think my roasts certainly compare to commercial roasts. But every now and then I get a roast that blows me away, and it must lay in the nuances of that particular roasting process... for example, I miss place the tea towel and end up burning my fingers pulling the pan out, which results in me swearing a lot and taking longer to dump the beans. Then there are the roasts where everything goes smoothly and i get the beans in the cooler sooner etc etc.

                      There are so many variables, and by the sounds of it they have a far greater effect than I could have imagined.

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                      • #26
                        Re: First roasts with data logger

                        Great info everyone!!  I used to do around 300-350 grams green initially in my old BM, which was smaller and had a square pan.  The current one is rectangular with 2 paddles, and seems to do 600-650 grams comfortably.  You are probably right in the bean mass retaining a fair bit of heat at the end, maybe I need to start raising my gun earlier?

                        Yep there are heaps of variable, I guess it very much like searching for the GOD SHOT itself, only adjust one thing at a time and see how that changes the result, do the same with the roasting.  I started to take notes about 20-30 roasts ago, on 1c and 2c times, bean mass start/finish, and notes on the flavours, to try and find the great roasts and replicate them, and keep notes on the beans that tasted good to me. With the data logger and software, this is so much easier, as you can bring up the previous GOD ROAST (have I created a new CS word??  [smiley=grin.gif] ) template from the past and try and replicate it.

                        The other thing I have started to do, is keep some roasted beans for longer than they normally last me (1 week), as I have discovered flavours come out of some beans towards the end of week 2/start week 3 that were just not there earlier.  A classic example is the Yirgacheffe, I tried it a a couple of times and my tasting notes said things like a bit bland/not much character/nothing special etc.  I tried some 2 weeks post roast and they flavours were simply transformed and I now like them!  Last time I roasted the Yirgacheffe, I had an espresso each morning, and a flat white at night, everyday for almost 2 weeks using the same beans, and you could taste the flavours developing every day!  A bit off topic but might good info for people like myself who may have never discovered this as my beans get drunk too quickly!!

                        Speaking of car bits and coffee, how is this for a zany idea for travellers:  Make up a drum roaster, with spiral fins on outside, placed inside a larger (non rotating drum), fitted on the end of the exhaust pipe.  The exhaust gases flow around the roast drum, the fins will cause it to rotate, and you can roast coffee as you drive!!  Sorry officer, I didnt realise I was going 130, I was just trying to hit second crack...  [smiley=cheesy.gif]

                        I need a coffee....

                        Cheers

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                        • #27
                          Re: First roasts with data logger

                          Originally posted by 2F3C3A232F204E0 link=1318770716/25#25 date=1319541390
                          The exhaust gases flow around the roast drum, the fins will cause it to rotate, and you can roast coffee as you drive!!
                          Imagine how long the de-gas would take!

                          But maybe the Carbon Monoxide would help preserve the beans :-?

                          Comment


                          • #28
                            Re: First roasts with data logger

                            Originally posted by 272E22202D77410 link=1318770716/24#24 date=1319539736
                            I will definitely try extending my temp that extra few degrees at the end of second crack in my next roast.
                            Hi VBM
                            Just to clarify - the extra few degrees in my roast is from the start of 2C (therefore around 30sec-1minute into 2C) - I imagine that a few extra degrees past the end of 2C would give you a nice shade of ebony!

                            Comment


                            • #29
                              Re: First roasts with data logger

                              One more quick question: The beanbay decaf, it states to roast by temp to just prior to 2C, I am guessing the 2C of decaf will be similar to "normal" beans? Or does one need to do one decaf roast to 2C to see what the temp is (on the setup used).

                              Cheers

                              Comment


                              • #30
                                Re: First roasts with data logger

                                Hmmmm never actually roasted decaf -will have to try!

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